body {
  background: #008694;
  font: 12px/20px "黑体", arial;
  -webkit-user-select: none;
}

header {
    display: block;
    margin: 0 auto;
    width: 500px;
    text-align: center;
}

header h1 {
    font-family: Arial;
    font-size: 40px;
    font-weight: bold;
}

#time_box{
    z-index: 4;
    font-size: 24px;
    color: #fa3c3c;
    font-weight: 700;
    text-shadow: 2px 2px 3px rgba(0, 0, 0, 3);
}

#box_container{
    width: 300px;
    height: 400px;
    margin: 50px auto;
    background-color: #55d769;
    border: 5px solid #000;
    position: relative;
}

.grid {
    width: 100px;
    height: 100px;
    background-color: #fff;
    /*border: 1px solid #000;*/
    position: absolute;
}

.block {
    width: 100px;
    height: 100px;
    /*border: 1px solid #000;*/
    font-family: Atial;
    font-weight: bold;
    font-size: 20px;
    color: #fff;
    text-align: center;
    position: absolute;
    margin-top: 1px;
}

.gameover{
    display: block;
    margin: 0 auto;
    width: 300px;
    text-align: center;
    vertical-align: middle;
    position: absolute;
}

.gameover p{
    font-family: Atial;
    font-size: 50px;
    color: white;
    margin: 50px auto;
    margin-top: 150px;
}

.gameover span{
    font-family: Atial;
    font-size: 50px;
    color: white;
    margin: 50px auto;
}

#restartgamebutton {
    display: block;
    margin: 20px auto;
    width: 180px;
    padding: 10px 10px;
    background-color: #8f7a66;
    font-family: Arail;
    font-size: 30px;
    color: white;
    text-decoration: none;
    border-radius: 8px;
}

#restartgamebutton:hover {
    background-color: #9f8b77;
}